In order to meet wireless data traffic demands that have increased after 4th Generation (4G) communication system commercialization, efforts to develop an improved 5G communication system or a pre-5G communication system have been made. For this reason, the 5G communication system or the pre-5G communication system is called a beyond 4G network communication system or a post LTE system.
In order to achieve a high data transmission rate, an implementation of the 5G communication system in a mmWave band (for example, 60 GHz band) is being considered. In the 5G communication system, technologies such as beamforming, massive Multi-Input Multi-Output (MIMO), Full Dimensional MIMO (FD-MIMO), array antenna, analog beam-forming, and large scale antenna are discussed to mitigate propagation path loss in the mmWave band and increase propagation transmission distance.
Further, technologies such as an evolved small cell, an advanced small cell, a cloud Radio Access Network (cloud RAN), an ultra-dense network, Device to Device communication (D2D), a wireless backhaul, a moving network, cooperative communication, Coordinated Multi-Points (CoMP), and interference cancellation have been developed to improve the system network in the 5G communication system.
In addition, the 5G system has developed Advanced Coding Modulation (ACM) schemes such as Hybrid FSK and QAM Modulation (FQAM) and Sliding Window Superposition Coding (SWSC), and advanced access technologies such as Filter Bank Multi Carrier (FBMC), Non Orthogonal Multiple Access (NOMA), and Sparse Code Multiple Access (SCMA).
The SCMA has been spotlighted as a multi-access technology that can support a plurality of terminals in an Internet of Things environment by sharing and using time-frequency resources. However, results so far have been achieved under an assumption of accurate synchronization and accurate channel estimation, and there is a lack of research on a channel estimation and synchronization method in the SCMA-based communication system. The SCMA-based communication system uses Ndata Resources Elements (REs) based on one Orthogonal Frequency Division Multiplexing (OFDM) symbol in data transmission, but should use Npilot REs based on one OFDM symbol as reference signals when using Demodulation Reference Signals (DMRSs) for channel estimation. Ndata and Npilot are determined as shown in equation (1) below.
                                          N            data                    =                      L            ×                          N              K                                      ,                              N            pilot                    =          L                                    (        1        )            
In equation (1), L corresponds to a length of a subcarrier used for data transmission in a frequency band, and it is assumed that symbol power per RE is 1. In an SCMA-based communication system, the number of REs used as pilots in the channel estimation using the conventional DMRS increases
  K  Ntimes compared to the number of REs required for data transmission. Further, in a frequency selective fading channel that changes according to a frequency, the conventional DMRS does not maintain orthogonality and thus a channel estimation performance deteriorates.
Accordingly, a method of generating a DMRS which allows efficient channel estimation in the SCMA-based communication system and transmitting/receiving a signal is required.